I've searched and can't exactly find what I'm looking for. I wan't to go turbo on my h22 running 12 lbs of boost in the near future. I know I'll have to sleeve the block as well as many other things, but my question is what kind of performance loss would happen if I bored my engine to 89mm and had it sleeved now? I know I'm filling a larger space with the same amout of air, just wondering if it would be bad. I'm the kind of person that likes to do things in stages.

 

why not turbo the stock bore, and then bore it out later. your power loss would be minimal but noticable. i have never done this though so don't quote me! the problem is tuning the motor right when you plan on doing everything in steps.

 

not to sound like a idiot but im just so scare about boosting a stock block with stock internals even if I'm only using 7 lbs.

 

What if I were to also ad crower stage two cams when I bore I know I can sell them for turbo cams.

 

what not run mahle pistons in the stock sleeves...

 

Sounding like a loser, I'm a highschool senior and can not boost until in college due to the fact I have a very protective mom. Thats why recently I have been thinking about just starting with some new cams and a larger bore.

 

there is no sence in buying new cams at all! stock cams are fine if you boost. i would only get cams if i were planning on running all motor. as far as your bottom end goes, the only reason you will notice a power loss, is when you change your compression. the bore will have no effect. I would defenitly lower the compression to around 9:1. I dont think you can run forged pistons without sleeving the block. So if you are going to do a rebuild, start with the bottom end, the head should hold up fine on that amount of boost.

 

thanks. I know this is turning the topic completely around but if I were to go all motor would I see more gains with crower stage 2 cams it it were bored out?

 

yeah you would. cams would do more that way i think. but just go with higher compression if you want to make good power all motor.

 

thanks still kinda new to all this stuff. Love learning though.

 

better to be safe than sorry i agree, but....... you can resleeve, get new low compression pistons 400-500 bucks and spend about 800-900 bucks for the sleeve job or you can use mahle as stated before and just get lower comression pistons. there is a very nice topic on using mahle pistons without resleeving here on h-t. only reason for sleeving is because of stock ringlands and forged pistons. 12psi isn't insanely high so its okay not to not sleeve. use the stock bore though. if you need to rebore in the future due to problems you got 88mm and 89mm to go with. if you start out at 89mm your dangersously thin on the walls while boosting. n/a is a different story. as far as stage 2 cams. i hear stock cams are best because they have less overlap when turboing or get turbo cams. some are ya some are nay on this one. search on this one though. you can save money here as well by using what you got. in fact if i get to boost in a few years i am going the mahle route without resleeving, stock cams, and just change out the stock rods. i will be going for 10-12psi. don't really have a hp goal in mind. just what ever that amount of psi will yeild. i will have a very good tuner so i am sure we can get me at the least 325whp considering the setup i will go with.